Nathaniel Chun Professor ScarcelliPLS 352

Nathaniel Chun
Professor ScarcelliPLS 352.01
5/31/18
Should the United States Replace Coal with Solar Energy?
Should the United States Replace Coal with Solar Energy? The four different sectors of energy use are transportation, industrial, residential, and electricity. “Within the total United States energy consumption, coal is 16.1%, petroleum is 36.2%, and solar is 0.5%. However, for electricity generation, coal is 33.2%, petroleum is 32.7%, and solar is 0.6%.” (Coal, IER). From the 2016 data from the Institute for Energy Research, we can see solar is not being used that much by the United States. There are a lot of pros and cons with switching, but the main reason to switch or not is the bigger picture of climate change. My research question is aimed to answer much bigger questions. Is climate change or global warming going to get worse as we keep using coal, and therefore we should use energy that is renewable? Is it perhaps too late to switch? Has the earth perhaps reached it’s tipping point and even if we switch to renewable energy there is so much pollution that climate change can continue without the need of our input anymore? Hence my question, should the United States even bother to replace coal with solar energy?
Coal is “a fossil fuel and is the altered remains of prehistoric vegetation that originally accumulated in swamps and peat bogs. The energy we get from coal today comes from the energy that plants absorbed from the sun millions of years ago.” (What is Coal). There are four types of coal Anthracite, Bituminous, Subbituminous, and Lignite. “Anthracite contains 86%–97% carbon, and generally has the highest heating value of all ranks of coal. Anthracite accounted for less than 1% of the coal mined in the United States in 2015. All of the anthracite mines in the United States are in northeastern Pennsylvania. Anthracite is mainly used by the metals industry. Bituminous coal contains 45%–86% carbon. Bituminous coal in the United States is between 100 and 300 million years old. Bituminous coal is the most abundant rank of coal found in the United States, and it accounted for 45% of total U.S. coal production in 2015. Bituminous coal is used to generate electricity and is an important fuel and raw material for making iron and steel. West Virginia, Kentucky, Illinois, Pennsylvania, and Indiana were the five main bituminous coal-producing states in 2015, accounting for 73% of total bituminous production. Subbituminous coal typically contains 35%–45% carbon, and it has a lower heating value than bituminous coal. Most subbituminous coal in the United States is at least 100 million years old. About 47% of total U.S. coal production in 2015 was subbituminous and nearly 90% was produced in Wyoming. Lignite contains 25%–35% carbon and has the lowest energy content of all coal ranks. Lignite coal deposits tend to be relatively young and were not subjected to extreme heat or pressure. Lignite is crumbly and has high moisture content, which contributes to its low heating value. Lignite accounted for 8% of total U.S. coal production in 2015. About 90% of total lignite production is mined in Texas and North Dakota in 2015, where it is mostly used to generate electricity. A facility in North Dakota also converts lignite to synthetic natural gas and pipes it to natural gas consumers in the eastern United States.” (Coal, EIA).
The pros of using coal are it’s inexpensive, there’s a lot of it, the infrastructure is already in place from our ancestors, it’s a reliable energy source, it can be converted into different forms to burn cleaner energy, and it creates jobs. As mentioned before, there are four types of coal Anthracite, Bituminous, Subbituminous, and Lignite. Their corresponding “price per 2,000 pounds is, $97.91, $51.57, $14.63, and $22.36.” (Coal Prices, EIA). That is a relatively cheap source of energy that is economically friendly. Not only is it relatively cheap, there is a lot of it on our planet. “The most comprehensive national assessment of U.S. coal resources was published by the U.S. Geological Survey (USGS) in 1975, which indicated that as of January 1, 1974, coal resources in the United States totaled 4 trillion short tons. Although more recent regional assessments of U.S. coal resources have been conducted by the USGS, a new national-level assessment of U.S. coal resources has not been conducted.” (Coal Reserve, EIA). The EIA published three measures but I will be looking at two. “Demonstrated Reserve Base (DRB) is the sum of coal in both measured and indicated resource categories of reliability. The DRB represents 100% of the in-place coal that could be mined commercially at a given time. EIA estimates the DRB at about 476 billion short tons, of which about 69% is underground mineable coal.” (Coal Reserve, EIA). “Estimated recoverable reserves include only the coal that can be mined with today’s mining technology after considering accessibility constraints and recovery factors. EIA estimates U.S. recoverable coal reserves at about 254 billion short tons, of which about 58% is underground mineable coal.” (Coal Reserve, EIA). Even with today’s technology for mining, we have approximately 147 (254*.58) billion short tons that is mineable and can be used for the creation of energy. “Based on U.S. coal production in 2016 of about 0.73 billion short tons, the recoverable coal reserves would last about 348 years, and recoverable reserves at producing mines would last about 23 years. The actual number of years that those reserves will last depends on changes in production and reserves estimates.” (Coal Reserve, EIA). The statistics from EIA.gov, prove and show that there is a lot of coal left and the potential gets higher if we keep improving our technology of mining for coal. This leads to the next pro of using coal. Our infrastructure is already in place and this lowers the cost of coal dramatically. It’s not just the fact that coal is cheap, but because our infrastructure is in place, we don’t need to spend more money building solar panels, wind turbines, water dams, etc. The process to get clean coal is “a refining called catalytic gasification to convert coal into methane or substitute natural gas. In their process, coal is mixed with a catalyst and fed into a gasifier: a tall, narrow, metal cylindrical container. Inside the gasifier, the coal and the catalyst are combined with steam and subjected to pressure. That causes a chemical reaction that converts them into carbon monoxide and hydrogen. GreatPoint says the key to its new technology is the catalyst it uses. Perlman says it’s a combination of readily available metals, but so far, the ingredients are secret.

Because of that catalyst, GreatPoint’s process works at a lower temperature than other technologies, which makes the process much cheaper. The catalyst also enables GreatPoint to separate out about half of the carbon dioxide, a chief cause of climate change. (The company plans to sell that carbon dioxide to be injected into oil or gas wells to facilitate production.) Other pollutants also are removed at the plant, which makes the product much cleaner than the synthesis gas produced by other gasification processes.” (Shogren, 2006). With the process of gasification, we don’t need to switch to a renewable energy. We can keep costs down by not building new infrastructure for renewable energy and just build a few catalytic gasification plants to convert coal into clean energy. Lastly, using coal creates jobs. There is a job market out there to go mine coal, transport coal, convert coal to clean energy, and burn coal. These aren’t the cleanest or most high paying jobs, but it does create jobs for people in this country.
The cons of using coal are that it’s harmful to the environment, there are potential health risks, there is limited supply, it is expensive to transport, it is expensive to produce clean coal, and there are future consequences we cannot fix if we keep using coal. Burning coal releases a bunch of nasty and harmful pollutants like carbon dioxide, sulfur dioxide, nitrous oxides, methane, particulate matter or soot, and mercury. Breathing in these pollutants in high doses or even low doses over a long period of time can be deadly to the human body. It affects our lungs and basically poisons us.
Solar energy is energy from the sun that the earth gets daily. “The sun has produced energy for billions of years and is the ultimate source for all of the energy sources and fuels that we use today. People have used the sun’s rays (solar radiation) for thousands of years for warmth and to dry meat, fruit, and grains. Over time, people developed devices (technologies) to collect solar energy for heat and to convert it into electricity.” (Solar, EIA). There are three types of solar power photovoltaic systems, solar thermal power plants, and solar thermal collectors. “Solar photovoltaic (PV) devices, or solar cells, change sunlight directly into electricity. Small PV cells can power calculators, watches, and other small electronic devices. Arrangements of many solar cells in PV panels and arrangements of multiple PV panels in PV arrays can produce electricity for an entire house. Some PV power plants have large arrays that cover many acres to produce electricity for thousands of homes.” (Solar, EIA). There are three main types of thermal power plants linear concentrating system, solar power towers, and solar dish/engine systems. “Linear concentrating systems collect the sun’s energy using long, rectangular, curved (U-shaped) mirrors. The mirrors focus sunlight onto receivers (tubes) that run the length of the mirrors. The concentrated sunlight heats a fluid flowing through the tubes. The fluid is sent to a heat exchanger to boil water in a conventional steam-turbine generator to produce electricity. There are two major types of linear concentrator systems: parabolic trough systems, where receiver tubes are positioned along the focal line of each parabolic mirror, and linear Fresnel reflector systems, where one receiver tube is positioned above several mirrors to allow the mirrors greater mobility in tracking the sun. A linear concentrating collector power plant has a large number, or field, of collectors in parallel rows that are typically aligned in a north-south orientation to maximize solar energy collection. This configuration enables the mirrors to track the sun from east to west during the day and concentrate sunlight continuously onto the receiver tubes. A solar power tower system uses a large field of flat, sun-tracking mirrors called heliostats to reflect and concentrate sunlight onto a receiver on the top of a tower. Sunlight can be concentrated as much as 1,500 times. Some power towers use water as the heat-transfer fluid. Advanced designs are experimenting with molten nitrate salt because of its superior heat transfer and energy storage capabilities. The thermal energy-storage capability allows the system to produce electricity during cloudy weather or at night. Solar dish/engine systems use a mirrored dish similar to a very large satellite dish. To reduce costs, the mirrored dish is usually composed of many smaller flat mirrors formed into a dish shape. The dish-shaped surface directs and concentrates sunlight onto a thermal receiver, which absorbs and collects the heat and transfers it to an engine generator. The most common type of heat engine used in dish/engine systems is the Stirling engine. This system uses the fluid heated by the receiver to move pistons and create mechanical power. The mechanical power runs a generator or alternator to produce electricity.

Solar dish/engine systems always point straight at the sun and concentrate the solar energy at the focal point of the dish. A solar dish’s concentration ratio is much higher than linear concentrating systems, and it has a working fluid temperature higher than 1,380°F. The power-generating equipment used with a solar dish can be mounted at the focal point of the dish, making it well suited for remote locations, or the energy may be collected from a number of installations and converted into electricity at a central point.” (Solar Thermal Power Plants, EIA). “People use solar thermal energy to heat water and air. The two general types of solar heating systems are passive systems and active systems. Passive solar space heating happens when the sun shines through the windows of a building and warms the interior. Building designs that optimize passive solar heating usually have south-facing windows that allow the sun to shine on solar heat-absorbing walls or floors during the winter. The solar energy heats the building by natural radiation and convection. Window overhangs or shades block the sun from entering the windows during the summer to keep the building cool. Active solar heating systems use a collector and a fluid that absorbs solar radiation. Fans or pumps circulate air or heat-absorbing liquids through collectors and then transfer the heated fluid directly to a room or to a heat storage system. Active water heating systems usually have a tank for storing solar heated water. (Solar Thermal Collectors, EIA).

The pros of using solar are it’s renewable, it also produces jobs, solar powered systems do not produce air pollutants and solar panels are on top of buildings so they do not cause any more harm to the landscape/environment. Solar, unlike coal is renewable because we are using the sun, which is an energy source that is everlasting. Coal is a material created over millions of years and once we run out we won’t have any more for many generations. Solar also doesn’t produce pollutants. However, the creation of photovoltaic cells/panels, solar towers, and mirrors will create pollutants since the only way to create them now is by using coal. But once we switch to all solar, there will be no more pollutants from burning coal. The cons of using solar are that it has a huge upfront cost, the amount of sunlight the earth gets changes daily and is seasonal, and sunlight intensity varies on where you are on the earth.